U.S. patent number 4,867,168 [Application Number 07/229,634] was granted by the patent office on 1989-09-19 for apparatus for simulating inspection equipment.
This patent grant is currently assigned to The Secretary of State for the United Kingdom Atomic Energy Authority in Britain and Northern Ireland. Invention is credited to Peter G. Bentley, Francis G. Latham, Phillip G. J. Stoor.
United States Patent |
4,867,168 |
Stoor , et al. |
September 19, 1989 |
**Please see images for:
( Certificate of Correction ) ** |
Apparatus for simulating inspection equipment
Abstract
Apparatus for simulating inspection equipment, e.g. ultrasonic
NDT equipment or ultrasonic medical diagnostics equipment,
comprises a test body, a simulated probe for scanning over the
body, a probe position monitor, inspection data storage, a display
and a central processor for correlating display of the inspection
data with scanning movement of the probe. The inspection data is
derived from non-simulated scanning of for example a structure
containing defects and the ultrasonic waveforms obtained during
such non-simulated scanning may be stored in memory for providing a
realistic display during simulated scanning of the test body. The
simulated probe may incorporate an ultrasonic device for the
purpose of sensing the degree of coupling between the simulated
transducer and the test body and the output of the device may be
used to modify the inspection data to provide a displayed signal
which is dependent on the coupling achieved by the operator.
Inventors: |
Stoor; Phillip G. J. (Lymm,
GB), Bentley; Peter G. (Dorchester, GB),
Latham; Francis G. (Warrington, GB) |
Assignee: |
The Secretary of State for the
United Kingdom Atomic Energy Authority in Britain and Northern
Ireland (London, GB2)
|
Family
ID: |
8198133 |
Appl.
No.: |
07/229,634 |
Filed: |
August 8, 1988 |
Current U.S.
Class: |
600/416; 434/262;
600/407; 703/6 |
Current CPC
Class: |
G09B
9/00 (20130101); G09B 23/286 (20130101) |
Current International
Class: |
G09B
23/00 (20060101); G09B 23/28 (20060101); G09B
9/00 (20060101); A61B 008/00 (); G09B 023/28 () |
Field of
Search: |
;128/653,660.01
;364/413.13,413.25,578 ;73/1DV ;434/262,267 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jaworski; Francis
Attorney, Agent or Firm: Hinds; William R.
Claims
We claim:
1. Apparatus for simulating inspection equipment comprising a
simulated test body, a simulated transducer which can be scanned
manually or automatically under the control of an operator over
said simulated body, means for monitoring the position co-ordinates
of the simulated transducer during such scanning, storing means
comprising non-volatile memory for digitally storing, for each of a
range of possible positions of the simulated transducer, inspection
data representative of such data obtained in the course of
non-simulated scanning of a non-simulated body, means for
selectively effecting loading of a volatile memory with part of the
inspection data from the non-volatile memory in dependence upon the
instantaneous position of the simulated transducer, and means
responsive to said monitoring means for retrieving from said
volatile memory inspection data corresponding to the positional
co-ordinates of the simulated transducer whereby scanning of the
simulated transducer over the simulated body is accompanied by the
production of inspection data correlated with the scanning
movement.
2. Apparatus as claimed in claim 1 in which said loading means is
operable to effect loading of the volatile memory with inspection
data associated with a range of positions around said instantaneous
position.
3. Apparatus as claimed in claim 2 including means responsive to
the degree of coupling between the simulated transducer and the
test body for modifying the retrieved inspection data.
4. Apparatus as claimed in claim 3, including digital to analogue
conversion means for translating the retrieved digital inspection
data into analogue signals, and means for visually displaying the
analogue signals, said modifying means being arranged to vary the
amplitude of said analogue signals in dependence upon said degree
of coupling.
5. Apparatus as claimed in claim 3, in which said modifying means
comprises a stress wave generator and stress wave carrier
incorporated in said simulated transducer, the stress wave carrier
having an end face which is spaced from the generator and is
substantially flush with, or constitutes a surface which, in use,
is intended to contact said test body, the stress wave generator
being operable to launch stress wave pulses into the carrier for
reflection at the end face of the carrier whereby the strength of
the reflected signal provides an indication of the effectiveness of
contact between the simulated transducer and the simulated test
body.
6. Apparatus as claimed in claim 3, in which the simulated test
body is contoured to simulate part of a human body.
7. Apparatus for simulating inspection equipment comprising a
simulated test body, a simulated transducer which can be scanned
manually or automatically under the control of an operator over
said simulated body, means for monitoring the position co-ordinates
of the simulated transducer during such scanning, means for
digitally storing for each of a range of possible positions of said
simulated transducer inspection data representative of such data
obtained in the course of non-simulated scanning of a non-simulated
body, means responsive to said monitoring means for retrieving from
said storing means inspection data corresponding to the positional
co-ordinates of the simulated transducer whereby scanning of the
simulated transducer over the simulated body is accompanied by the
production of inspection data correlated with the scanning
movement, means responsive to the degree of coupling between the
simulated transducer and the test body for modifying the retrieved
inspection data, digital to analogue conversion means for
translating the retrieved digital inspection data into analogue
signals, means for visually displaying the analogue signals, said
modifying means being arranged to vary the amplitude of said
analogue signals in dependence upon said degree of coupling and
comprising a stress wave generator and stress wave carrier
incorporated in said simulated transducer, the stress wave carrier
having an end face which is spaced from the generator and is
substantially flush with, or constitutes a surface which, in use,
is intended to contact said test body, the stress wave generator
being operable to launch stress wave pulses into the carrier for
reflection at the end face of the carrier whereby the strength of
the reflected signal provides an indication of the effectiveness of
contact between the simulated transducer and the simulated test
body.
8. Apparatus as claimed in claim 7, in which the simulated body is
contoured to simulate part of a human body.
Description
This invention relates to apparatus for simulating inspection
equipment, e.g. for the purpose of training personnel in
non-destructive testing (NDT) techniques such as ultrasonic
inspection or medical diagnostics using ultrasonics techniques.
At present, NDT training is carried out with the aid of test blocks
having artificially implanted defects and NDT trainees carry out
scanning, e.g. with a conventional ultrasonic probe which may be
operated manually or automatically. This suffers from a number of
drawbacks in that: such test blocks are expensive to produce and
tend to be relatively immobile so that trainees have to attend
wherever the test block happens to be located; additional test
blocks may need to be produced in order to offer a reasonably wide
range of training experience; the security of the test block may be
compromised in the sense that details of defects and locations may
be passed to trainees in advance of a testing session; and only
defects capable of being manufactured can be implanted.
One object of the present invention is to provide apparatus for
simulating NDT equipment which avoids the use of test blocks with
artificially implanted defects.
According to one aspect of the present invention there is provided
apparatus for simulating inspection equipment comprising a
simulated test body, a simulated transducer which can be scanned
manually or automatically under the control of an operator over
said simulated body, means for monitoring the position co-ordinates
of the simulated transducer during such scanning, storing means
comprising non-volatile memory for digitally storing, for each of a
range of possible positions of said simulated transducer,
inspection data representative of such data obtained in the course
of non-simulated scanning of a non-simulated body, means for
selectively effecting loading of a volatile memory with part of the
inspection data from the non-volatile memory in dependence upon the
instantaneous position of the simulated transducer, and means
responsive to said monitoring means for retrieving from said
volatile memory inspection data corresponding to the positional
co-ordinates of the simulated transducer whereby scanning of the
simulated transducer over the simulated body is accompanied by the
production of inspection data correlated with the scanning
movement.
The retrieved inspection data may be transferred to display means
for viewing by an operator.
In this manner, in the case of NDT inspection the operator is given
the impression of carrying out a real time NDT examination of a
substantial defect-containing structure even though in reality the
simulated test body may merely consist of thin stainless steel
plate material which may be fabricated to give the appearance of a
substantial structure.
In an alternative application, the retrieved inspection data may be
fed to data gathering equipment.
The simulated transducer may resemble, or be constituted by, a
conventional transducer (e.g. an ultrasonic transducer) although it
will be understood that where an actual transducer is employed it
will not be operational in the conventional sense but will merely
be provided to give the operator a realistic impression of
performing an inspection.
In one embodiment of the invention, the monitoring means may
include a digitising tablet as used in for example computer aided
draughting, the digitising tablet being incorporated in the
simulated test block, for example underneath the stainless steel
plate described above. The simulated transducer in this event may
include an electrical coil inductively coupled through the
stainless steel plate to the digitising tablet and the latter may
provide an output representing the coil position in XY
co-ordinates.
The non-volatile memory may comprise a magnetic disc or tape. The
volatile memory, such as semi-conductor random access memory, may
be loaded with the inspection data corresponding to a range of
positions around the "instantaneous" position of the simulated
transducer and is updated in response to each new position of the
simulated transducer registered by the monitoring means. Transfer
of the inspection data from the volatile memory to the display
means or data gathering equipment may be effected by a central
processor and the monitoring means may be constituted by a
peripheral processor so that time delays in determining the
"instantaneous" position of the simulated transducer can be
minimised.
According to a second aspect of the invention there is provided
apparatus for simulating inspection equipment comprising a
simulated test body, a simulated transducer which can be scanned
manually or automatically under the control of an operator over
said simulated body, means for monitoring the position co-ordinates
of the simulated transducer during such scanning, means for
digitally storing for each of a range of possible positions of said
simulated transducer, inspection data representative of such data
obtained in the course of non-simulated scanning of a non-simulated
body, means responsive to said monitoring means for retrieving from
said storing means inspection data corresponding to the positional
co-ordinates of the simulated transducer whereby scanning of the
simulated transducer over the simulated body is accompanied by the
production of inspection data correlated with the scanning
movement, and means responsive to the degree of coupling between
the simulated transducer and the test body for modifying the
retrieved inspection data.
Preferably, the apparatus includes digital to analogue conversion
means for translating the retrieved digital inspection data into
analogue signals and means for visually displaying the analogue
signals, said modifying means being arranged to vary the amplitude
of said analogue signals in dependence upon said degree of
coupling.
Conveniently, said modifying means comprises a stress wave
generator and stress wave carrier incorporated in said simulated
transducer, the stress wave carrier having an end face which is
spaced from the generator and is substantially flush with, or
constitutes a surface which, in use, is intended to contact said
test body, the stress wave generator being operable to launch
stress wave pulses into the carrier for reflection at the end face
of the carrier whereby the strength of the reflected signal
provides an indication of the effectiveness of contact between the
simulated transducer and the simulated test body.
To promote further understanding of the invention an embodiment
will now be described by way of example only with reference to the
accompanying drawing in which:
FIG. 1 is a schematic block diagram illustrating simulating
apparatus in accordance with the invention; and
FIG. 2 is a diagrammatic sectional view of the "transducer"
Referring now to FIG. 1, the system for simulating for example
ultrasonic non-destructive testing comprises a mini-computer 10
coupled with a disc drive 12 and buffer storage 14. The disc drive
12 is loaded with a disc containing all the software for the system
together with ultrasonic defect data. The defect data is
transferable from the disc to the buffer storage 14 for rapid
access by the mini-computer, as explained below.
The defect data is derived from non-simulated NDT ultrasonic
scanning of a specimen or specimens known to contain defects. The
specimen(s) may be deliberately manufactured with implanted defects
or may be a structure for which a "real-life" ultrasonic NDT
examination has been recorded. Typically, the defect data will
consist of a large number of digitised ultrasonic waveforms and
their corresponding position co-ordinates.
The test block is simulated by a stainless steel plate 16 beneath
which is located a high resolution digitising tablet of the type
used in computer-aided draughting. The simulated transducer 18 is
movable over the surface of the plate 16 and incorporates a coil 34
(see FIG. 2) inductively coupled with the digitising tablet so that
the latter can provide an output in digital form representing the
positional co-ordinates of the simulated transducer 18 at any
instant. This output is monitored by a peripheral processor 20 and
put into a form suitable for access within the software routines of
the mini-computer 10. Since this is done independently of the
mini-computer, no time delay occurs when the mini-computer requests
data relating to the position of the simulated transducers.
During scanning of the simulated test block, the mini-computer 10
as part of its program cycle repeatedly interrogates the peripheral
processor to obtain the current positional data for the simulated
transducer 10 and, using that data, then retrieves from the
corresponding ultrasonic waveform either directly from the buffer
storage 14 if already available or from the disc via the buffer
storage. The digitised waveform data is transferred to a display
22, such as a conventional flaw detector display, via attenuator
circuitry 26 (to be described later) and a function generator 24
which converts the digitised data into analogue form to provide a
reconstructed waveform on the display which may be
indistinguishable from the waveform that an operator would expect
to see on observing an actual defect embedded in a steel test block
or, on-site, in a manufactured item such as a pressure vessel.
The mini-computer 10 is programmed so that, on obtaining positional
data from the peripheral processor 20, the buffer storage 14 is
loaded with the waveform corresponding to that particular
positional data (if not already available in the buffer storage)
and also the waveforms corresponding to a limited range of
positions surrounding the current position of the simulated
transducer 18. In this way, the waveform data for subsequent
displacement of the simulated transducer within that limited range
is immediately available from the buffer storage thereby avoiding
delay in reading waveform data from disc to the buffer storage.
Even when the buffer storage 14 already contains the required
waveform data for a new position of the transducer, the buffer
storage may be updated with waveform data corresponding to a
predetermined range of positions centred on the new position.
The function of the attenuator circuitry 26 is to modify the
analogue signals applied by the D/A converter 24 to the display 22
so that the displayed signal strength is varied in dependence upon
the electromechanical coupling between the simulated transducer 18
and the specimen 16, as detected by coupling detection circuitry
28.
Referring to FIG. 2, the simulated probe 18 comprises a housing 30
which accommodates the coil 34 energised via lead 38 and which, in
terms of outward appearance, may closely resemble the appearance of
a conventional fully functional ultrasonic transducer. The housing
30 has a contact face 32 which, in use, is contacted with the
surface of the specimen 16 through a conventional ultrasonic
couplant gel 36 so that good electromechanical coupling can be
achieved. However, it will be understood that for simulation
purposes it is not necessary for there to be good electromechanical
coupling because there is no actual transmission of ultrasonic
energy into the specimen 16 for the purpose of testing the
specimen. Nevertheless, it is desirable that use of the simulating
apparatus should closely mirror use of real equipment so that, if
the operator fails to secure good electromechanical coupling, the
results obtained are correspondingly degraded. To this end, the
apparatus includes means for sensing the extent of
electromechanical coupling between the transducer 18 and the
specimen 16.
In the illustrated embodiment, the sensing means comprises an
ultrasonic signal generator, e.g. a piezoelectric crystal 40,
bonded to a coupling bar 41 which may be of metal, preferably
having an acoustic impedance close to that of the specimen 16.
Coupling detection circuitry 28 includes a pulse generator for
electrically pulsing the crystal 40 via lead 42 whereby pulsed
ultrasound is launched into the coupling bar 42. The ultrasound
pulses are reflected at the end face 46 of the coupling bar 41, the
end face being substantially flush with the contact face 32 of the
housing 30. If the end face 44 is not well coupled with the
specimen then a strong reflected signal is obtained but as the
degree of coupling increases, ultrasonic energy is lost from the
bar 41 into the specimen. By pulsing the bar 41 at a frequency
which gives resonant conditions of the bar/crystal combination, a
reflected signal can be picked up, via lead 44, which has an
amplitude which is reproducible and is a function of the distance
of the fully-gelled end face 46 from the surface of specimen 16. In
practice, at conventional frequencies used in ultrasound testing,
e.g. 1 MHz and above, this function tends to be frequency-dependent
and complex because of interference effects in the couplant gel
film. It has been found that, by operating at lower frequencies,
e.g. of the order 250 KHz, these frequency-dependent effects can be
reduced or avoided without reduction in the skill required on the
part of the operator to maintain good electromechanical
coupling.
The reflected signals received by detection circuitry 28 are
translated into a control voltage which represents the degree of
coupling and is applied to voltage-controlled attenuator 26 which
attenuates the analogue signals from the D/A converter 24 to a
greater or lesser extent depending on the quality of coupling
achieved. In this way, the output of the display 22 reflects the
quality of the coupling achieved and the operator can, by
appropriate manipulation of the transducer while observing the
display, check whether or not he is achieving satisfactory
coupling.
From the foregoing it will be seen that the system as described
above affords the following advantages:
a. Real data from real flaws is used to generate the waveforms
presented to the inspection equipment and/or inspector. These can
come from:
1. Deliberately introduced defects in test blocks.
2. Real defects that may exist due to manufacturing in the type of
structure to be encountered by test personnel.
3. Predicted defects that cannot yet be artificially manufactured,
but are known to be possible. It is envisaged that theoretical
modelling work could supply the data such that these defects may be
experienced by inspectors or their test equipment before they are
encountered in practice.
b. The data is repeatable and accurate since the waveforms are
recalled from memory without distortion or degradation. The data
may be copied or transmitted to other test facilities where
simulator systems exist. No differences will exist between the data
presented to inspectors and test equipment in the various locations
and therefore comparisons and standards will be maintained over
large distances in dispersed training and validation sites.
c. The system is quickly disassembled for transport to other
locations, and the waveform data may be transmitted over electronic
links between sites and countries. This is not the case at present
with very large test blocks.
d. The system is cheaper than using test blocks and can take the
place of many test blocks since it is so easily re-configured.
e. The security of the system relies upon the fact that an
inspector cannot know from one session to another where the
simulator programmer has placed a defect, either in orientation,
position, depth or what type it is. This is not the case with test
blocks, since if the location of defects are known or passed on to
third parties the security of that test block is compromised.
Although the invention is described above in relation to NDT of
defect-containing structures, the invention also has application to
medical inspection techniques using for example ultrasonics. In
this instance, the test body may be contoured to simulate for
example the trunk of a human body and a probe is used to scan over
the simulated trunk, means being provided to monitor the position
of the probe (e.g. in 3 dimensions). In this case, pre-recorded
inspection data obtained from ultrasonic inspection of a living
human body may be stored digitally by means of a laser-readable
optical disc and the stored data may be retrieved in dependence
upon the "instantaneous" position of the probe relative to the
simulated trunk and processed to produce a C-scan display which
will change as a probe moves across the trunk. The optical disc may
be used in conjunction with volatile memory so that at any instant
the memory is loaded with inspection data associated with the
current position of the probe and, in addition, data associated
with a range of positions lying within a zone around the current
probe position.
* * * * *